kopia lustrzana https://github.com/peterhinch/micropython-samples
44 wiersze
1.2 KiB
Python
44 wiersze
1.2 KiB
Python
@micropython.asm_thumb
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def reverse(r0, r1): # bytearray, len(bytearray)
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add(r4, r0, r1)
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sub(r4, 1) # end address
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label(LOOP)
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ldrb(r5, [r0, 0])
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ldrb(r6, [r4, 0])
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strb(r6, [r0, 0])
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strb(r5, [r4, 0])
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add(r0, 1)
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sub(r4, 1)
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cmp(r4, r0)
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bpl(LOOP)
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def test():
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a = bytearray([0, 1, 2, 3]) # even length
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reverse(a, len(a))
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print(a)
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a = bytearray([0, 1, 2, 3, 4]) # odd length
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reverse(a, len(a))
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print(a)
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# Bit reverse an 8 bit value
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def rbit8(v):
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v = (v & 0x0f) << 4 | (v & 0xf0) >> 4
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v = (v & 0x33) << 2 | (v & 0xcc) >> 2
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return (v & 0x55) << 1 | (v & 0xaa) >> 1
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# Bit reverse a 16 bit value
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def rbit16(v):
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v = (v & 0x00ff) << 8 | (v & 0xff00) >> 8
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v = (v & 0x0f0f) << 4 | (v & 0xf0f0) >> 4
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v = (v & 0x3333) << 2 | (v & 0xcccc) >> 2
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return (v & 0x5555) << 1 | (v & 0xaaaa) >> 1
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# Bit reverse a 32 bit value
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def rbit32(v):
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v = (v & 0x0000ffff) << 16 | (v & 0xffff0000) >> 16
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v = (v & 0x00ff00ff) << 8 | (v & 0xff00ff00) >> 8
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v = (v & 0x0f0f0f0f) << 4 | (v & 0xf0f0f0f0) >> 4
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v = (v & 0x33333333) << 2 | (v & 0xcccccccc) >> 2
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return (v & 0x55555555) << 1 | (v & 0xaaaaaaaa) >> 1
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